It is desired in the prior art to determine if a transit vehicle is occupying a given track signal block and to provide an occupancy indication in relation to the roadway track by establishing a signal shunt circuit for a vehicle control signal between a pair of conductive members associated with that track. For example, the track signal block occupancy of a steel wheel vehicle operating with a track comprising a pair of steel rails has been determined in relation to a signal from a speed command transmitter positioned at one end of a particular track signal block that is electrically shunted between the rails by the vehicle occupying that signal block to prevent the signal being sensed by a receiver positioned at the other end of the same track signal block as taught by U.S. Pat. Nos. Re. 27,472 and 3,966,149. In addition, for a vehicle having a vehicle carried transmitter providing a door open control signal that couples with a wayside receiver when the vehicle is located in a station, it is known in the prior art to provide a logic apparatus responsive to a track shunt signal concurrent with the receipt of the door control signal to establish the satisfactory operation of the track signal shunt operation for vehicle occupancy determination. It is known to sense the speed command signal received by the rear signal receiver of the transit vehicle passing through a signal block when the shunt provided by the vehicle should prevent the rear vehicle receiver from receiving that signal to determine that a shunt failure condition might be present. It is known in the prior art to provide mechanical sensing devices for the electrical shunt contacts or brush devices at each side of the track for a rubber-tired vehicle to determine that those shunt providing devices are still physically provided and operating.
It is known in the prior art to provide a power collection apparatus for a rubber-tired vehicle operative with a roadway track having a central guide beam as shown in U.S. Pat. Nos. 4,168,770 and 4,090,452, and including power rails that do not continue through track switches and including control signal and ground rails that do continue through a track switch, with the power collector shoes being guided through a track switch by coupling those power collector shoes with the ground collector shoe and the control signal collector shoe that are positioned by the respective continuous ground rail and control signal rail. This same vehicle is known to include an electrical shunt circuit apparatus carried by the vehicle and connected between a conductive member coupled with the ground rail and a conductive member coupled with the signal rail for providing a desired command signal shunt to indicate track signal block occupancy.